Kyle Crouse: Who owns the rights to the Mega Man characters that originated in Archie? (e.g. if Capcom willed it, could Tempo appear in Mega Man 12?)
Ian Flynn: As far as I'm aware, Capcom owns everything, and yeah; they could bring her back.
Kyle Crouse: Well... what are they waiting for?
Ian Flynn: Mega Man 12 I guess.
Of course, Ian is joking about Mega Man 12. But the important point here is that there's been long-standing speculation about who owns characters that don't originate from the games—whether it's the author who created them, or the company or publisher they worked for.
There are exceptions—such as Marty, who belongs to Yoshihiro Iwamoto—but in the case of the Archie Mega Man characters, Capcom retains full ownership. If they choose, we could absolutely see some of these original characters appear in future games, merchandise, or other projects.